Variable Power Supply 0-24V

Variable Power Supply 0-24V

The circuit described here is of an economical smooth variable power supply which offers 0V to 24V. It provides all controls and short circuit protection with acceptable regulation and a ripple free supply and yet uses very few components.

The transformer used is a readily available 12V-0-12V, 2A type connected at the end terminals for 24V, 1A output. After rectification and filtering, a constant reference voltage is obtained by the 24V, 500mW zener diode.

Variable Power Supply 0-24V circuit diagram

R1 1kΩ  0.5W
R2 820Ω  0.5W
R3 0.6Ω  1W
VR1 470Ω  LIN
VR3 10Ω 1W
C1 2200µF 50V
C2 200µF 50V
D1 5A Diode Bridge
D2 2A Diode
D3 24V 500mw zener
T1 2N 3055
T2 SL 100
T3 BC 148B
X1 SEC 24V, 1AMP

The pots used for voltage variation are 23mm carbon-film linear type and for current limit 10 ohm, 1w wirewound type is used. All the components can be connected on a group board. Necessary heatsinks should be provided for both SL100 and 2N3055.

Please send your ideas, those are very important for our success…

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14 comments on “Variable Power Supply 0-24V
  1. Jay says:

    What is voltage regulation of 12V and 24V at full load current of 1 Amp?

  2. Mahadev Pawase says:

    Thanx for the help. I have designed 0-24V power supply using your given ckt diagram & It is working smoothly.

    Thanx Thanx alot.

  3. kushal says:

    Can You Please mention how is the above circuit designed..? I mean the caluculations of resistence values and choosing particular transistors..?

  4. Cherikhan says:

    This circuit is simple and usefull but not really stabilized its working without any error correction . thanks.

  5. puneet says:

    dear sir

    what is the basic difference between smps and the above mentioned ckt

    • admin says:

      Smps is high efficient. So it save more energy. But this type (linear) power supply is simple,low risk for electrocution

  6. CBhaskar says:

    If I would make the circuit for upto 0-12Volt & upto 2 Amp variable power supply, what changes are required to incorporate in this existing Circuit? Please guide.

  7. rav says:

    Can I used this circuit for my 3amp transformer?

  8. Can I replace the SL100 with any other metallic transistor like 2N2222? Will it still produce the same power?

    And what if I just want it to max output 16v?

  9. ANJITHA.R says:

    Can I use regulator ICs (LM317) instead of zener diode in the same circuit???

  10. Chakroni says:

    Can i replace sl100 with any other metallic transistor? Will it still produce the same power

  11. Have anyone tested? Does this Circuit Work?

    • testingBeta says:

      it will , but not from 1 volt, it may go to 0.7-1v no less. also sinc it has no feedback, you output voltage will drop on even small loads ( tested a variation of thisand looking for better designs with feedback)

  12. supun says:

    I want to upgrade this circuit for get output 3Amp. How it do? Please help or reply my email

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